1. Field of the Invention
The present invention relates to a system and method for controlling running of a vehicle using a car navigation system, such as an automobile route guiding system. More particularly, the present invention relates to a system and method for controlling running of a vehicle based on the state of the road curves ahead of the vehicle.
2. Description of Related Art
Car navigation systems employed on many automobiles can detect the current travel position of the vehicle and can compute the travel route for guiding the vehicle from the current position to the target arrival position using the map information and GPS functionality or the like. In addition, in recent years, many control technologies have been proposed that perform combined control of the speed of the vehicle by means of the car navigation system functions.
For example, as described in Japanese Kokai Patent Application No. Hei 6[1994]-36187, when a curve in the road ahead of where the vehicle travels is detected, the target vehicle speed for the vehicle when passing through the curve is computed from the magnitude of the curve. Based on the computed target vehicle speed, the target deceleration for realizing the target vehicle speed is computed. When it is determined that the vehicle is traveling too fast, the vehicle is decelerated under control before reaching the curve, so that the vehicle can pass through the curve at the optimum speed.
Usually, the map information stored in conventional navigation systems pertaining to the position and shape of curves is relatively accurate. However, for some roads the accuracy is low and differs significantly from the actual road conditions.